my $w; $w = AnyEvent->timer(
    after => 0,
    interval => 5,
    cb => sub {
        $session->write('5 seconds have passed');
    }
);

my $timeout_timer; $timeout_timer = AnyEvent->timer(
    after => 0,
    interval => 30,
    cb => sub {
        undef $w;
        undef $timeout_timer;
        $session->write('Timeout after 30 seconds');
        $w_cond->send();
    }
);